Wireless communication method, terminal device and network device

ABSTRACT

Provided are a wireless communication method, a terminal device and a network device. The wireless communication method is used for the terminal device, and when the network device connected to the terminal device is switched from a source network device to a target network device, the connection between the terminal device and the source network device and the connection between the terminal device and the target network device are both maintained. Said method comprises: when the terminal device satisfies a first condition, releasing the connection between the terminal device and a source network device. In the implementations of the present application, during switching of the terminal device, the connection between the terminal device and the source network device and the connection between the terminal device and the target network device are both maintained, effectively reducing the delay in the process of switching the network device connected to the terminal device from the source network device to the target network device.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation application of U.S. patentapplication Ser. No. 17/318,413 filed on May 12, 2021, which is acontinuation application of International PCT Application No.PCT/CN2018/117720, having an international filing date of Nov. 27, 2018.The contents of the above-identified applications are herebyincorporated by reference.

TECHNICAL FIELD

Implementations of the present application relate to the field ofcommunication, and more specifically, to a wireless communicationmethod, a terminal device and a network device.

BACKGROUND

In an existing handover procedure, after a terminal device receives aRadio Resource Control (RRC) reconfiguration message, it willreconfigure Packet Data Convergence Protocol (PDCP)/Radio Link Controlprotocol (RLC)/Media Access Control (MAC)/low layer and the likeaccording to handover configuration in the RRC reconfiguration message,so as to correspond to a stack of a target base station.

Since only one set of PDCP/RLC/MAC/low layer is maintained by theterminal device in the whole handover process, therefore, during thehandover process, the terminal device needs to stop sending andreceiving uplink/downlink (UL/DL) data at the same time at a source basestation, and establish a connection with the target base station, thus atime delay is introduced.

Therefore, how to reduce a time delay of terminal device in a handoverprocess is a technical problem to be solved urgently in this field.

SUMMARY

A wireless communication method, a terminal device and a network deviceare provided, which can effectively reduce a time delay in a process ofswitching the network device connected with the terminal device from asource network device to a target network device, and specify a detailedsolution of releasing a connection between the terminal device and thesource network device, as well as a data transmission method between theterminal device and the network device and the detailed solution ofsending a status report by the terminal device.

In a first aspect, a wireless communication method is provided, which isapplied to a terminal device. When a network device connected to theterminal device is switched from a source network device to a targetnetwork device, a connection between the terminal device and the sourcenetwork device and a connection between the terminal device and thetarget network device are both maintained.

The method includes: releasing the connection between the terminaldevice and the source network device when the terminal device satisfiesa first condition.

In a second aspect, a wireless communication method is provided, whichis applied to a source network device. When a network device connectedwith a terminal device is switched from the source network device to atarget network device, a connection between the terminal device and thesource network device and a connection between the terminal device andthe target network device are both maintained.

The method includes: releasing the connection between the source networkdevice and the terminal device when the source network device satisfiesa first condition.

In a third aspect, a wireless communication method is provided, which isapplied to a terminal device. When a network device connected with theterminal device is switched from a source network device to a targetnetwork device, a connection between the terminal device and the sourcenetwork device and a connection between the terminal device and thetarget network device are both maintained.

The method includes: sending and/or receiving a Packet Data ConvergenceProtocol (PDCP) Protocol Data Unit (PDU) by using a new secret keyand/or Robust Header Compression (RoHC) to when the terminal devicesatisfies a second condition, wherein the new secret key and/or RoHC isdifferent from an old secret key and/or RoHC, and the old secret keyand/or RoHC is a secret key and/or RoHC which is used by the terminaldevice when communicating with the source network device and/or thetarget network device before the new secret key and/or robust headercompression (RoHC) is used.

In a fourth aspect, a wireless communication method is provided, whichis applied to a target network device. When a network device connectedwith a terminal device is switched from a source network device to thetarget network device, a connection between the terminal device and thesource network device and a connection between the terminal device andthe target network device are both maintained.

The method includes: sending and/or receiving a packet data convergenceprotocol (PDCP) protocol data unit (PDU) by using a new secret keyand/or robust header compression (RoHC) to when the target networkdevice satisfies a second condition, wherein the new secret key and/orRoHC is different from an old secret key and/or RoHC, and the old secretkey and/or RoHC is a secret key and/or RoHC which is used by theterminal device when communicating with the source network device and/orthe target network device before the new secret key and/or robust headercompression (RoHC) is used.

In a fifth aspect, a wireless communication method is provided, which isapplied to a source network device. When a network device connected witha terminal device is switched from the source network device to a targetnetwork device, a connection between the terminal device and the sourcenetwork device and a connection between the terminal device and thetarget network device are both maintained.

The method includes: sending and/or receiving a packet data convergenceprotocol (PDCP) protocol data unit (PDU) by using a new secret keyand/or robust header compression (RoHC) when the source network devicesatisfies a second condition, wherein the new secret key and/or RoHC isdifferent from an old secret key and/or RoHC, and the old secret keyand/or RoHC is a secret key and/or RoHC which is used by the terminaldevice when communicating with the source network device and/or thetarget network device before the new secret key and/or robust headercompression (RoHC) is used.

In a sixth aspect, a wireless communication method is provided, which isapplied to a terminal device. When a network device connected with aterminal device is switched from the source network device to a targetnetwork device, a connection between the terminal device and the sourcenetwork device and a connection between the terminal device and thetarget network device are both maintained. The method includes:triggering the terminal device to send a packet data convergenceprotocol (PDCP) status report when the terminal device satisfies a thirdcondition.

In a seventh aspect, a terminal device is provided, configured toperform the method in the above first aspect or each implementationthereof. Specifically, the terminal device includes function modules forperforming the method in the above first aspect or each implementationthereof.

In an eighth aspect, a network device is provided, configured to performthe method in the above second aspect or each implementation thereof.Specifically, the network device includes function modules forperforming the method in the above second aspect or each implementationthereof.

In a ninth aspect, a terminal device is provided, configured to performthe method in the above third aspect or various implementations thereof.Specifically, the terminal device includes function modules configuredto perform the method in the above third aspect or each implementationthereof.

In a tenth aspect, a network device is provided, configured to performthe method in the above fourth aspect or each implementation thereof.Specifically, the network device includes function modules forperforming the method in the above fourth aspect or each implementationthereof.

In an eleventh aspect, a network device is provided, configured toperform the method in the above fifth aspect or each implementationthereof. Specifically, the network device includes function modules forperforming the method in the above fifth aspect or each implementationthereof.

In a twelfth aspect, a terminal device is provided, configured toperform the method in the above sixth aspect or each implementationthereof. Specifically, the terminal device includes function modules forperforming the method in the above sixth aspect or each implementationthereof.

In a thirteenth aspect, a terminal device is provided, including aprocessor and a memory. The memory is configured to store a computerprogram, and the processor is configured to call and run the computerprogram stored in the memory to perform the method in the above firstaspect or each implementation thereof.

In a fourteenth aspect, a network device is provided, including aprocessor and a memory. The memory is configured to store a computerprogram, and the processor is configured to call and run the computerprogram stored in the memory to perform the method in the above secondaspect or each implementation thereof.

In a fifteenth aspect, a terminal device is provided, including aprocessor and a memory. The memory is configured to store a computerprogram, and the processor is configured to call and run the computerprogram stored in the memory to perform the method in the above thirdaspect or each implementations thereof.

In a sixteenth aspect, a network device is provided, including aprocessor and a memory. The memory is configured to store a computerprogram, and the processor is configured to call and run the computerprogram stored in the memory to perform the method in the above fourthaspect or each implementation thereof.

In a seventeenth aspect, a network device is provided, including aprocessor and a memory. The memory is configured to store a computerprogram, and the processor is configured to call and run the computerprogram stored in the memory to perform the method in the above fifthaspect or each implementation thereof.

In a eighteenth aspect, a terminal device is provided, including aprocessor and a memory. The memory is configured to store a computerprogram, and the processor is configured to call and run the computerprogram stored in the memory to perform the method in the above sixthaspect or each implementation thereof.

In a nineteenth aspect, a chip is provided, configured to implement themethod in any one of the above first to sixth aspects or in variousimplementations thereof. Specifically, the chip includes a processorconfigured to call and run a computer program from a memory to enable adevice disposed with the chip to perform the method in any one of theabove first to sixth aspects or each implementation thereof.

In a twentieth the aspect, a computer-readable storage medium isprovided, configured to store a computer program to cause a computer toperform the method in any one of the above first to sixth aspects oreach implementation thereof.

In a twenty-first aspect, a computer program product is provided,including computer program instructions, and the computer programinstructions cause a computer to perform the method in any one of theabove first to sixth aspects or each implementation thereof.

In a twenty-second aspect, a computer program is provided, which, whenrun on a computer, causes the computer to perform the method in any oneof the above first to sixth aspects or each implementation thereof.

Based on the technical solution, when a network device connected with aterminal device is switched from a source network device to a targetnetwork device, connections between the terminal device and the sourcenetwork device as well as the target network device are maintained atthe same time, which can effectively reduce a time delay in a process ofswitching the network device connected with the terminal device from thesource network device to the target network device. In addition, adetailed solution of releasing the connection between the terminaldevice and the source network device, the data transmission methodbetween the terminal device and the network device and the detailedsolution of sending a status report by the terminal device arespecified.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an example of an application scenario of the presentapplication.

FIG. 2 is a DC architecture applicable to a wireless communicationmethod according to an implementation of the present application.

FIG. 3 is an eMBB architecture applicable to a wireless communicationmethod according to an implementation of the present application.

FIG. 4 is a schematic flowchart of a wireless communication methodaccording to implementations of the present application.

FIG. 5 is another schematic flowchart of a wireless communication methodaccording to implementations of the present application.

FIG. 6 is another schematic flowchart of a wireless communication methodaccording to implementations of the present application.

FIG. 7 is a schematic block diagram of a communications device accordingto implementations of the present application.

FIG. 8 is another schematic block diagram of a communications deviceaccording to implementations of the present application.

FIG. 9 is a schematic block diagram of a terminal device according to animplementation of the present application.

FIG. 10 is a schematic block diagram of a communication device accordingto an implementation of the present application.

FIG. 11 is a schematic block diagram of a chip according to animplementation of the present application.

DETAILED DESCRIPTION

FIG. 1 shows a wireless communication system 100 to which animplementation of the present application is applied. The wirelesscommunication system 100 may include a base station 110 and at least oneterminal device 120 located within a coverage range of the base station110.

The base station 110 may be a device that communicates with a terminaldevice.

The base station 110 may provide communication coverage for a specificgeographic area and may communicate with the terminal device (e.g., UE)located within the coverage area. Optionally, the base station 110 maybe a base station (gNB) in an NR system, or a radio controller in aCloud Radio Access Network (CRAN), or the network device may be a relaystation, an access point, a vehicle-mounted device, a wearable device,or a network device in a future evolved Public Land Mobile Network(PLMN), etc.

The terminal device 120 may be mobile or fixed. Optionally, the terminaldevice 120 may be referred to as an access terminal, a User Equipment(UE), a subscriber unit, a subscriber station, a mobile station, amobile platform, a remote station, a remote terminal, a mobile device, auser terminal, a terminal, a wireless communication device, a useragent, or a user apparatus. The access terminal may be a cellular phone,a cordless phone, a Session Initiation Protocol (SIP) phone, a WirelessLocal Loop (WLL) station, a Personal Digital Assistant (PDA), a handhelddevice with a wireless communication function, a computing device, orother processing device connected to a wireless modem, a vehicle-mounteddevice, a wearable device, a terminal device in a future 5G network, ora terminal device in a future evolved PLMN, or the like.

The wireless communication system 100 also includes a core networkdevice 130 that communicates with the base station.

The core network device 130 may be a 5G Core (5GC) device, such as anAccess and Mobility Management Function (AMF), an Authentication ServerFunction (AUSF), or a User Plane Function (UPF), or a Session ManagementFunction (SMF). Optionally, the core network device 130 may also be anEvolved Packet Core (EPC) device of an LTE network, for example, aSession Management Function+Core Packet Gateway (SMF+PGW-C) device. Itshould be understood that SMF+PGW-C may realize the functions which canbe realized by the SMF and the PGW-C at the same time.

FIG. 1 shows one base station, one core network device and two terminaldevices as an example. Optionally, the wireless communication system 100may include multiple base station devices and other quantity of terminaldevices may be included in a coverage range of each base station, whichis not limited in the implementations of the present application.

FIG. 2 and FIG. 3 are examples of communication frameworks applicable toa wireless communication method according to an implementation of thepresent application.

It should be understood that the communication device shown in FIG. 2and FIG. 3 may be the terminal device 120 as shown in FIG. 1, or theaccess network device 110 as shown in FIG. 1, and may further be thecore network device 130 as shown in FIG. 1. Accordingly, the sourcenetwork device or the target network device shown in FIG. 2 and FIG. 3may be the terminal device 120 as shown in FIG. 1, or the access networkdevice 110 as shown in FIG. 1, and may further be the core networkdevice 130 as shown in FIG. 1. It should also be understood that theprotocol architectures shown in FIG. 2 and FIG. 3 are only examples.However, the implementations of the present application are not limitedthereto. For example, in other alternative implementations, thecommunication device may include more than two PDCP entities.

As shown in FIG. 2, the terminal device includes a first PDCP entity anda second PDCP entity as shown in FIG. 2.

Specifically, as shown in FIG. 2, the terminal device may include afirst Packet Data Convergence Protocol (PDCP) entity, a first Radio LinkControl (RLC) entity, a first Media Access Control (MAC) entity, asecond PDCP entity, a second RLC entity and a second MAC entity. Thesource network device includes a third PDCP entity, a third RLC entityand a third MAC entity. The target network device may include a fourthPDCP entity, a fourth RLC entity, and a fourth MAC entity.

Specifically, the first PDCP entity of the terminal device passesthrough the first RLC entity and the first MAC entity, and then reachesthe third MAC entity, the third RLC entity and the third PDCP entity ofthe source network device via an air interface. The second PDCP entityof the terminal device passes through the second RLC entity and thesecond MAC entity, and then reaches the fourth MAC entity, the fourthRLC entity and the fourth PDCP entity of the target network device viaan air interface.

Optionally, in the framework shown in FIG. 2, communication may beperformed between the third PDCP entity and the fourth PDCP entity.

Specifically, as shown in FIG. 3, the terminal device may only includeone PDCP entity, and further, the terminal device may further includeone PDCP entity, a first RLC entity, a first MAC entity, a second RLCentity and a second MAC entity. The source network device includes athird PDCP entity, a third RLC entity and a third MAC entity. The targetnetwork device may further include a fourth RLC entity and a fourth MACentity.

Specifically, the PDCP entity of the terminal device passes through thefirst RLC entity and the first MAC entity, and then reaches the thirdMAC entity, the third RLC entity and the third PDCP entity of the sourcenetwork device via an air interface. The PDCP entity of the terminaldevice further passes through the second RLC entity and the second MACentity, and then reaches the fourth MAC entity and the fourth RLC entityof the target network device via an air interface, and then reaches thethird PDCP entity of the source network device.

FIG. 4 is a schematic flow chart of a communication method according toan implementation of the present application.

As shown in FIG. 4, the method 200 may include S210.

In S210: when a first condition is satisfied, a connection between aterminal device and a source network device is released.

In some implementations of the present application, the communicationmethod 300 is applicable to a terminal device. When the network deviceconnected with the terminal device is switched from a source networkdevice to a target network device, the connection between the terminaldevice and the source network device and the connection between theterminal device and the target network device are both maintained.

That is, when the terminal device satisfies the first condition, theconnection between the terminal device and the source network device isreleased.

The first condition includes but is not limited to at least one of thefollowing:the terminal device has received a handover command, theterminal device has initiated a random access procedure, or the terminaldevice has sent a handover completion message. Specifically, thehandover command may be Radio Resource Control (RRC) reconfigurationinformation sent by the source network device to the terminal device.

Optionally, the random access procedure initiated by the terminal deviceincludes at least one of the following cases: the terminal device hassent a message 1, the terminal device has received a message 2, theterminal device has sent a message 3, or the terminal device hasreceived a message 4.

Optionally, after the terminal device satisfies the first condition fora certain time, the connection between the terminal device and thesource network device is released.

In other implementations of the present application, the communicationmethod shown in FIG. 4 is also applicable to a source network device.When the network device connected with the terminal device is switchedfrom the source network device to the target network device, theconnection between the terminal device and the source network device andthe connection between the terminal device and the target network deviceare both maintained.

That is, when the source network device satisfies the first condition,the connection between the source network device and the terminal deviceis released.

Optionally, the first condition includes at least one of the following:the source network device has sent a handover command, or the sourcenetwork device has received indication information sent by the terminaldevice or the target network device for indicating the source networkdevice to disconnect the connection between the terminal device and thesource network device.

The handover command may be RRC reconfiguration information sent by thesource network device to the terminal device. That is, after the sourcenetwork device sends the RRC reconfiguration information to the terminaldevice, the connection between the source network device and theterminal device is released.

For another example, the source network device releases the connectionbetween the source network device and the terminal device afterreceiving the indication information sent by the terminal device. Theterminal device sends the indication information to the source networkdevice when at least one of the following conditions is met: theterminal device has received a handover command, the terminal device hasinitiated a random access procedure, the terminal device has sent ahandover completion message, the terminal device has sent a message 1,the terminal device has received a message 2, the terminal device hassent a message 3, or the terminal device has received a message 4.

For another example, the source network device releases the connectionbetween the source network device and the terminal device afterreceiving the indication information sent by the target network device.The target network device may send the indication information to thesource network device after receiving handover completion informationsent by the terminal device. Or, the target network device may send theindication information to the source network device after receiving atleast one of the following messages: the target network device hasreceived the message 1, the target network device has sent the message2, the target network device has received the message 3, or the targetnetwork device has sent the message 4.

In other words, the time moment for triggering the target network deviceor the terminal device to send the indication information includes butis not limited to: a random access message.

For example, any one or at least one of the message 1, the message 2,the message 3 or the message 4.

Optionally, after the terminal device satisfies the first condition fora certain time, the connection between the terminal device and thesource network device is released.

It should be understood that FIG. 4 is only an example of animplementation of the present application, and should not be consideredas a limitation on the implementations of the present application.

For example, in other alternative implementations, the first conditionmay be other trigger conditions. For example, the first condition may bea message in a non-contention access process.

FIG. 5 is a schematic flowchart of another communication methodaccording to an implementation of the present application.

As shown in FIG. 5, the method 300 may include S310.

In S310: when a second condition is satisfied, a PDCP protocol data unit(PDU) is sent or received by using a new secret key and/or RoHC. The newsecret key and/or RoHC is different from an old secret key and/or RoHC,and the old secret key and/or RoHC is a secret key and/or RoHC which isused by the terminal device when communicating with the source networkdevice and/or the target network device before the new secret key and/orrobust header compression (RoHC) is used.

In some implementations of the present application, the communicationmethod 300 may be applied to a terminal device. When a network deviceconnected with the terminal device is switched from a source networkdevice to a target network device, the connection between the terminaldevice and the source network device and the connection between theterminal device and the target network device are both maintained.Therefore, when the terminal device satisfies the second condition, theterminal device sends and/or receives a PDCP PDU by using the new secretkey and/or RoHC.

Optionally, the terminal device send and/or receive the PDCP PDU byusing the new secret key and/or RoHC after satisfying the secondcondition and after a certain time interval.

For example, after the terminal device satisfies the second conditionand after a certain time interval, the terminal device sends the PDCPPDU sent by the source network device to the source network deviceand/or receives the PDCP PDU sent by the source network device by usingthe new secret key and/or RoHC.

For another example, after the terminal device satisfies the secondcondition and after a certain time interval, the terminal device sendsthe PDCP PDU sent by the target network device to the target networkdevice and/or receives the PDCP PDU sent by the target network device byusing the new secret key and/or RoHC.

It should be understood that the certain time interval may be a presettime period, or a time period negotiated by the terminal device with thesource network device and/or the target network device, or a time periodindicated by the network, which is not specifically limited in theimplementations of the present application.

Optionally, within a certain time after the terminal device satisfiesthe second condition, the terminal device sends and/or receives the PDCPPDU by using the old secret key and/or RoHC.

For example, within a certain time after the terminal device satisfiesthe second condition, the terminal device sends the PDCP PDU sent by thesource network device to the source network device and/or receives thePDCP PDU sent by the source network device by using the old secret keyand/or RoHC.

For another example, within a certain time after the terminal devicesatisfies the second condition, the terminal device sends the PDCP PDUsent by the target network device to the target network device and/orreceives the PDCP PDU sent by the target network device by using the oldsecret key and/or RoHC.

Optionally, the second condition includes at least one of the following:the terminal device has received a handover command, the terminal devicehas initiated a random access procedure, or the terminal device has senta handover completion message.

Optionally, the random access procedure initiated by the terminal deviceincludes at least one of the following cases: the terminal device hassent a message 1, the terminal device has received a message 2, theterminal device has sent a message 3 or the terminal device has receiveda message 4.

Optionally, the terminal device discards a first data packet, whereinthe first data packet is a data packet that was not successfully sentbefore the terminal device satisfies the second condition and/or beforea certain time point after the terminal device satisfies the secondcondition.

Optionally, the terminal device retransmits a first data packet, whereinthe first data packet is a data packet that was not successfully sentbefore the terminal device satisfies the second condition and/or beforea certain time point after the terminal device satisfies the secondcondition.

The specific implementation modes of retransmission of the first datapacket by the terminal device will be described below.

Optionally, the terminal device retransmits the first data packet byusing the new secret key and/or RoHC.

For example, the terminal device retransmits the first data packet tothe source network device by using the new secret key and/or RoHC.

For another example, the terminal device retransmits the first datapacket to the target network device by using the new secret key and/orRoHC.

Optionally, the terminal device retransmits the first data packet byusing the old secret key and/or RoHC.

For example, the terminal device retransmits the first data packet tothe source network device by using the old secret key and/or RoHC.

For another example, the terminal device retransmits the first datapacket to the target network device using the old secret key and/orRoHC.

In other words, when the terminal device retransmits the first datapacket, the terminal device may use the old secret key and/or RoHC, ormay use the new secret key and/or ROHC, which is not limited in theimplementations of the present application.

Further, when the terminal device retransmits the first data packet, theterminal device may retransmit the first data packet to the sourcenetwork device or the target network device, which is not specificallylimited in the implementations of the present application.

In a specific implementation, the terminal device encrypts and/orcompresses the PDCP PDU corresponding to the first data packet accordingto the old secret key and/or ROHC or according to the new secret keyand/or RoHC, and sends the encrypted and/or compressed PDCP PDU.

Optionally, the first data packet may include a PDCP PDU which has beensent by the terminal device and whose automatic repeat requestacknowledgement (ARQ ACK) has not been received before the terminaldevice satisfies the second condition.

Optionally, the first data packet may include a PDCP PDU which has beensent by the terminal device and whose automatic repeat requestacknowledgement (ARQ ACK) has not been received before a certain timepoint after the terminal device satisfies the second condition.

The above description is for an uplink retransmission of the terminaldevice, but the implementations of the present application are notlimited thereto.

For example, the terminal device may further receive a retransmissiondata packet sent by the source network device and/or the target networkdevice.

Optionally, the terminal device receives a second data packetretransmitted by the target network device by using the old secret keyand/or ROHC, or by using the new secret key and/or RoHC.

Optionally, the target network device discards the second data packet.

The second data packet may be a data packet that was not successfullysent before the target network device satisfies the second conditionand/or before a certain time point after the target network devicesatisfies the second condition.

For example, the second data packet includes a PDCP PDU which has beensent by the target network device and whose automatic repeat requestacknowledgement (ARQ ACK) has not been received before the targetnetwork device satisfies the second condition, and/or the second datapacket includes a PDCP PDU which has been sent by the target networkdevice and whose ARQ ACK has not been received before a certain timepoint after the target network device satisfies the second condition.

Optionally, the terminal device receives a third data packetretransmitted by the source network device by using the old secret keyand/or ROHC, or by using the new secret key and/or RoHC.

Optionally, the source network device discards the third data packet.

The third data packet may be a data packet that was not successfullysent before the target network device satisfies the second conditionand/or before a certain time point after the target network devicesatisfies the second condition.

For example, the third data packet includes a PDCP PDU which has beensent by the source network device and whose automatic repeat requestacknowledgement (ARQ ACK) has not been received before the sourcenetwork device satisfies the second condition, and/or, the third datapacket includes a PDCP PDU which has been sent by the source networkdevice and whose ARQ ACK has not been received before a certain timepoint after the source network device satisfies the second condition.

In some other implementations of the present application, thecommunication method 300 may further be applied to a target networkdevice. When a network device connected with the terminal device isswitched from a source network device to a target network device, theconnection between the terminal device and the source network device andthe connection between the terminal device and the target network deviceare both maintained. Therefore, when the target network device satisfiesthe second condition, the target network device may send and/or receivea packet data convergence protocol (PDCP) protocol data unit (PDU) byusing a new secret key and/or robust header compression (RoHC) to,wherein the new secret key and/or RoHC is different from the old secretkey and/or RoHC, and the old secret key and/or RoHC is the secret keyand/or RoHC which is used by the terminal device when communicating withthe source network device and/or the target network device before thenew secret key and/or robust header compression (RoHC) is used.

Optionally, the target network device sends and/or receives the PDCP PDUby using the new secret key and/or RoHC after satisfying the secondcondition and after a certain time interval.

Optionally, within a certain time after the target network devicesatisfies the second condition, the target network device sends and/orreceives the PDCP PDU by using the old secret key and/or RoHC.

Optionally, the second condition includes at least one of the following:

the terminal device has initiated a random access procedure, or thetarget network device has received a handover completion message.

Optionally, the random access procedure initiated by the terminal deviceincludes at least one of the following cases:

the target network device has received a message 1, the target networkdevice has sent a message 2, the target network device has received amessage 3, or the target network device has sent a message 4.

Optionally, the target network device receives a first data packetretransmitted by the terminal device.

The first data packet is a data packet that was not successfully sentbefore the terminal device satisfies the second condition and/or beforea certain time point after the terminal device satisfies the secondcondition.

For example, the first data packet includes a PDCP PDU which has beensent by the terminal device and whose automatic repeat requestacknowledgement (ARQ ACK) has not been received before the terminaldevice satisfies the second condition, and/or the first data packetincludes a PDCP PDU which has been sent by the terminal device and whoseautomatic repeat request acknowledgement (ARQ ACK) has not been receivedbefore a certain time point after the terminal device satisfies thesecond condition.

Specifically, the target network device receives the first data packetretransmitted by the terminal device by using the old secret key and/orRoHC, or by using the new secret key and/or ROHC.

More specifically, the target network device receives the first datapacket retransmitted by the terminal device, and decrypts and/ordecompresses the first data packet according to the old secret keyand/or RoHC, or according to the new secret key and/or ROHC.

Optionally, the target network device discards the second data packet.

Optionally, the target network device retransmits the second data packetto the terminal device.

The second data packet is a data packet that was not successfully sentbefore the target network device satisfies the second condition and/orbefore a certain time point after the target network device satisfiesthe second condition.

For example, the second data packet includes a PDCP PDU which has beensent by the target network device and whose automatic repeat requestacknowledgement (ARQ ACK) has not been received before the targetnetwork device satisfies the second condition, and/or the second datapacket includes a PDCP PDU which has been sent by the target networkdevice and whose ARQ ACK has not been received before a certain timepoint after the target network device satisfies the second condition.

Specifically, the target network device retransmits the second datapacket to the terminal device by using the old secret key and/or RoHC,or by using the new secret key and/or ROHC.

In other implementations of the present application, the method 300 mayfurther be applied to a source network device. When a network deviceconnected with a terminal device is switched from the source networkdevice to a target network device, the connection between the terminaldevice and the source network device and the connection between theterminal device and the target network device are both maintained.Therefore, when the source network device satisfies the secondcondition, the source network device sends and/or receives a packet dataconvergence protocol (PDCP) protocol data unit (PDU) by using a newsecret key and/or robust header compression (RoHC), wherein the newsecret key and/or RoHC is different from the old secret key and/or RoHC,and the old secret key and/or RoHC is the secret key and/or RoHC whichis used by the terminal device when communicating with the sourcenetwork device and/or the target network device before the new secretkey and/or robust header compression (RoHC) is used, wherein the newsecret key and/or RoHC is different from an old secret key and/or RoHC,and the old secret key and/or RoHC is the secret key and/or RoHC whichis used by the terminal device when communicating with the sourcenetwork device and/or the target network device before the new secretkey and/or robust header compression (RoHC) is used.

Optionally, the source network device sends and/or receives the PDCP PDUby using the new secret key and/or RoHC after satisfying the secondcondition and after a certain time interval.

Optionally, within a certain time after the source network devicesatisfies the second condition, the source network device sends and/orreceives the PDCP PDU by using the old secret key and/or RoHC.

Optionally, the second condition includes at least one of the following:

the source network device has sent a handover command, or the sourcenetwork device has received indication information sent by the terminaldevice or the target network device for indicating the source networkdevice to send and/or receive the PDCP PDU by using the new secret keyand/or RoHC.

Specifically, the source network device receives the indicationinformation, and sends and/or receives indication information of PDCPPDU by using the new secret key and/or RoHC according to the indicationinformation.

For example, the source network device receives the indicationinformation sent by the terminal device when at least one of thefollowing is satisfied: the terminal device has received a handovercommand, the terminal device has initiated a random access procedure,the terminal device has sent a handover completion message, the terminaldevice has sent a message 1, the terminal device has received a message2, the terminal device has sent a message 3 or the terminal device hassent a message 4.

For another example, the source network device receives the indicationinformation sent by the target network device when at least one of thefollowing conditions is satisfied: the target network device hasreceived handover completion information, the target network device hasreceived the message 1, the target network device has sent the message2, the target network device has received the message 3, or the targetnetwork device has sent the message 4.

Optionally, the source network device receives a first data packetretransmitted by the terminal device.

The first data packet is a data packet that was not successfully sentbefore the target network device satisfies the second condition and/orbefore a certain time point after the target network device satisfiesthe second condition.

For example, the first data packet includes a PDCP PDU which has beensent by the terminal device and whose Automatic Repeat-request (ARQ)acknowledgement (ACK) has not been received before the terminal devicesatisfies the second condition, and/or the first data packet includes aPDCP PDU which has been sent by the terminal device and whose automaticrepeat request acknowledgement (ARQ ACK) has not been received before acertain time point after the terminal device satisfies the secondcondition.

Specifically, the target network device may receive the first datapacket retransmitted by the terminal device by using the old secret keyand/or RoHC, or by using the new secret key and/or ROHC.

More specifically, the source network device receives the first datapacket retransmitted by the terminal device, and decrypts and/ordecompresses the PDCP PDU corresponding to the first data packetaccording to the old secret key and/or RoHC or the new secret key and/orROHC.

Optionally, the source network device discards a third data packet.

Optionally, the source network device retransmits the third data packetto the terminal device.

The third data packet is a data packet that was not successfully sentbefore the target network device satisfies the second condition and/orbefore a certain time point after the target network device satisfiesthe second condition.

For example, the third data packet includes a PDCP PDU which has beensent by the source network device and whose automatic repeat requestacknowledgement (ARQ ACK) has not been received before the sourcenetwork device satisfies the second condition, and/or the third datapacket includes a PDCP PDU which has been sent by the source networkdevice and whose ARQ ACK has not been received before a certain timepoint after the source network device satisfies the second condition.

Specifically, the source network device retransmits the third datapacket to the terminal device by using the old secret key and/or RoHC,or by using the new secret key and/or ROHC.

FIG. 6 is a schematic flowchart of another communication methodaccording to an implementation of the present application. Thecommunication method 300 may be applied to a terminal device. When anetwork device connected with the terminal device is switched from asource network device to a target network device, the connection betweenthe terminal device and the source network device and the connectionbetween the terminal device and the target network device are bothmaintained; and the method 400 may include S410:

In S410, when the terminal device satisfies a third condition, theterminal device is triggered to send a packet data convergence protocol(PDCP) status report.

The PDCP status report may include the status of the PDCP PDU receivedby a PDCP receiving entity.

Optionally, the third condition includes at least one of the following:

the terminal device has received a handover command, the terminal devicehas initiated a random access procedure, or the terminal device has senta handover completion message.

Optionally, the random access procedure initiated by the terminal deviceincludes at least one of the following cases:

the terminal device has sent a message 1, the terminal device hasreceived a message 2, the terminal device has sent a message 3 or theterminal device has received a message 4.

Optionally, the terminal device is triggered to send the PDCP statusreport after the terminal device satisfies the first condition for acertain time. It should be understood that the certain time interval maybe a preset time period, a time period negotiated by the terminal devicewith the source network device and/or the target network device, or atime period indicated by the network, which is not specifically limitedin the implementations of the present application.

Optionally, in other alternative implementations, the method 400 may befurther applied to the source network device or the target networkdevice.

For example, when the method 400 is applied to the source networkdevice, when the source network device satisfies the third condition,the source network device is triggered to send the PDCP status report tothe terminal device.

For another example, when the method 400 is applied to the targetnetwork device, when the target network device satisfies the thirdcondition, the target network device is triggered to send the PDCPstatus report to the terminal device.

It should be understood that when the method 400 is applied to thesource network device or the target network device, the third conditionneeds to be adaptively modified.

For example, when the method 400 is applied to the target networkdevice, the third condition may be at least one of the following: thetarget network device has received the handover completion information,the target network device has received the message 1, the target networkdevice has sent the message 2, the target network device has receivedthe message 3, or the target network device has sent the message 4.

Similarly, when the method 400 is applied to the source network device,the third condition may be at least one of the following: the sourcenetwork device has sent the handover command, or the source networkdevice has received indication information sent by the terminal deviceor the target network device for indicating the source network device tosend the PDCP status report.

The preferred implementations of the present application have beendescribed in detail above with reference to the attached drawings, butthe present application is not limited to the specific details in theabove implementations. Within the technical conception of the presentapplication, various simple variations can be made to the technicalsolutions of the present application, and these simple variations allbelong to the protection scope of the present application.

For example, the specific technical features described in the abovespecific implementations can be combined in any suitable manner of thereis no contradiction. In order to avoid unnecessary repetition, variouspossible combinations are not explained separately in the presentapplication.

For another example, different implementations of the presentapplication can be combined arbitrarily, as long as they do not violatethe idea of the present application, they should also be regarded ascontents disclosed in the present application.

It should be understood that sequence numbers of the foregoing processesdo not mean execution sequences in various method implementations of thepresent application. The execution sequences of the processes should bedetermined according to functions and internal logic of the processes,and should not be construed as any limitation on the implementationprocesses of the implementations of the present application.

Method implementations of the present application are described indetail above in combination with FIGS. 1 to 6. Device implementations ofthe present application are described in detail below in combinationwith FIGS. 7 to 11.

FIG. 7 is a schematic block diagram of a communication device 500according to an implementation of the present application.

It should be understood that the communication device 500 may be aterminal device or a source network device for performing the method 200shown in FIG. 4.

In some implementations of the present application, the communicationdevice 500 may be a terminal device. When a network device connectedwith the terminal device is switched from a source network device to atarget network device, the connection between the terminal device andthe source network device and the connection between the terminal deviceand the target network device are both maintained. As shown in FIG. 7,the terminal device includes a release unit 510, wherein the releaseunit is configured to release the connection between the terminal deviceand the source network device when the terminal device satisfies a firstcondition.

Optionally, the first condition includes at least one of the following:

the terminal device has received a handover command, the terminal devicehas initiated a random access procedure, or the terminal device has senta handover completion message.

Optionally, the random access procedure initiated by the terminal deviceincludes at least one of the following cases:

the terminal device has sent a message 1, the terminal device hasreceived a message 2, the terminal device has sent a message 3, or theterminal device has received a message 4.

Optionally, the release unit 510 is specifically configured to:

release the connection between the terminal device and the sourcenetwork device after the terminal device satisfies the first conditionfor a certain time.

In some other implementations of the present application, thecommunication device 500 may be used as the source network device, andwhen the network device connected with the terminal device is switchedfrom the source network device to the target network device, theconnection between the terminal device and the source network device andthe connection between the terminal device and the target network deviceare both maintained. The source network device includes the release unit510, wherein the release unit is configured to release the connectionbetween the source network device and the terminal device when thesource network device satisfies a first condition.

Optionally, the first condition includes at least one of the following:

the source network device has sent a handover command, or the sourcenetwork device has received indication information sent by the terminaldevice or the target network device for indicating the source networkdevice to disconnect the connection between the terminal device and thesource network device.

Optionally, the terminal device further includes:

a communication unit, configured to receive the indication information.

Optionally, the communication unit is specifically configured to:receive the indication information sent by the terminal device when atleast one of the following is satisfied: the terminal device hasreceived a handover command, the terminal device has initiated a randomaccess procedure, the terminal device has sent a handover completionmessage, the terminal device has sent a message 1, the terminal devicehas received a message 2, the terminal device has sent a message 3, orthe terminal device has sent a message 4.

Optionally, the communication unit is specifically configured to:receive the indication information sent by the target network devicewhen at least one of the following conditions is satisfied: the targetnetwork device has received handover completion information, the targetnetwork device has received the message 1, the target network device hassent the message 2, the target network device has received the message3, or the target network device has sent message 4.

Optionally, the release unit is specifically configured to: release theconnection between the terminal device and the source network deviceafter the terminal device satisfies the first condition for a certaintime.

FIG. 8 is a schematic block diagram of a communication device 600according to an implementation of the present application.

In some implementations of the present application, the communicationdevice 600 may be a terminal device.

Specifically, when a network device connected with the terminal deviceis switched from a source network device to a target network device, theconnection between the terminal device and the source network device andthe connection between the terminal device and the target network deviceare both maintained. The terminal device includes a communication unit610; wherein when the terminal device satisfies a second condition, thecommunication unit 610 sends and/or receives packet data convergenceprotocol (PDCP) protocol data unit (PDU) by using a new secret keyand/or robust header compression (RoHC), wherein the new secret keyand/or RoHC is different from an old secret key and/or RoHC and the oldsecret key and/or RoHC is the secret key and/or RoHC which is used bythe terminal device when communicating with the source network deviceand/or the target network device before the new secret key and/or robustheader compression (RoHC) is used.

Optionally, the communication unit 610 is specifically configured to:send and/or receive the PDCP PDU by using the new secret key and/or RoHCafter the terminal device satisfies the second condition and after acertain time interval.

Optionally, the communication unit 610 is further configured to: sendand/or receive the PDCP PDU by using the old secret key and/or RoHCwithin a certain time after the terminal device satisfies the secondcondition.

Optionally, the second condition includes at least one of the following:the terminal device has received a handover command, the terminal devicehas initiated a random access procedure, or the terminal device has senta handover completion message.

Optionally, the random access procedure initiated by the terminal deviceincludes at least one of the following cases: the terminal device hassent a message 1, the terminal device has received a message 2, theterminal device has sent a message 3, or the terminal device hasreceived a message 4.

Optionally, the communication unit 610 is further configured to: discarda first data packet, wherein the third data packet is a data packet thatwas not successfully sent before the terminal device satisfies thesecond condition and/or before a certain time point after the terminaldevice satisfies the second condition.

Optionally, the communication unit 610 is further configured to:retransmit a first data packet, wherein the third data packet is a datapacket that was not successfully sent before the terminal devicesatisfies the second condition and/or before a certain time point afterthe terminal device satisfies the second condition.

Optionally, the communication unit 610 is specifically configured to:retransmit the first data packet by using the new secret key and/orRoHC.

Optionally, the communication unit 610 is specifically configured to:retransmit the first data packet by using the old secret key and/orRoHC.

Optionally, the communication unit 610 is specifically configured to:encrypt and/or compress the PDCP PDU corresponding to the first datapacket according to the old secret key and/or ROHC or according to thenew secret key and/or RoHC, and send the encrypted and/or compressedPDCP PDU.

Optionally, the first data packet includes a PDCP PDU which has beensent by the terminal device and whose automatic repeat requestacknowledgement (ARQ ACK) has not been received before the terminaldevice satisfies the second condition, and/or the first data packetincludes a PDCP PDU which has been sent by the terminal device and whoseautomatic repeat request acknowledgement (ARQ ACK) has not been receivedbefore a certain time point after the terminal device satisfies thesecond condition.

Optionally, the communication unit is further configured to: receive asecond data packet retransmitted by the target network device by usingthe old secret key and/or ROHC, or by using the new secret key and/orRoHC.

Optionally, the communication unit is further configured to: receive athird data packet retransmitted by the source network device by usingthe old secret key and/or ROHC, or by using the new secret key and/orRoHC.

In some implementations of the present application, the communicationdevice 600 may be a target network device.

Specifically, when a network device connected with a terminal device isswitched from a source network device to the target network device, theconnection between the terminal device and the source network device andthe connection between the terminal device and the target network deviceare both maintained. The network device includes the communication unit610; wherein when the target network device satisfies a secondcondition, the communication unit 610 sends and/or receives a packetdata convergence protocol (PDCP) protocol data unit (PDU) by using a newsecret key and/or robust header compression (RoHC), wherein the newsecret key and/or RoHC is different from an old secret key and/or RoHC,and the old secret key and/or RoHC is a secret key and/or RoHC which isused by the terminal device when communicating with the source networkdevice and/or the target network device before the new secret key and/orrobust header compression (RoHC) is used.

Optionally, the communication unit 610 is specifically configured to:send and/or receive the PDCP PDU by using the new secret key and/or RoHCafter the target network device satisfies the second condition and aftera certain time interval.

Optionally, the communication unit 610 is further configured to: sendand/or receive the PDCP PDU by using the old secret key and/or RoHCwithin a certain time after the target network device satisfies thesecond condition.

Optionally, the second condition includes at least one of the following:the terminal device has initiated a random access procedure, or thetarget network device has received a handover completion message.

Optionally, the random access procedure initiated by the terminal deviceincludes at least one of the following cases: the target network devicehas received a message 1, the target network device has sent a message2, the target network device has received a message 3, or the targetnetwork device has sent a message 4.

Optionally, the communication unit 610 is further configured to: receivea first data packet retransmitted by the terminal device.

Optionally, the communication unit 610 is specifically configured to:receive the first data packet retransmitted by the terminal device byusing the old secret key and/or ROHC, or by using the new secret keyand/or RoHC.

Optionally, the communication unit 610 is more specifically configuredto: receive the first data packet retransmitted by the terminal device,and decrypt and/or decompress the first data packet according to the oldsecret key and/or RoHC, or according to the new secret key and/or ROHC.

Optionally, the communication unit 610 is further configured to: discarda second data packet, wherein the second data packet is a data packetthat was not successfully sent before the target network devicesatisfies the second condition and/or before a certain time point afterthe target network device satisfies the second condition.

Optionally, the communication unit 610 is further configured to:retransmit a second data packet to the terminal device, wherein thesecond data packet is a data packet that was not successfully sentbefore the target network device satisfies the second condition and/orbefore a certain time point after the target network device satisfiesthe second condition.

Optionally, the communication unit 610 is specifically configured to:retransmit the second data packet to the terminal device by using theold secret key and/or ROHC, or by using the new secret key and/or RoHC.

Optionally, the second data packet includes a PDCP PDU which has beensent by the target network device and whose automatic repeat requestacknowledgement (ARQ ACK) has not been received before the targetnetwork device satisfies the second condition, and/or the second datapacket includes a PDCP PDU which has been sent by the target networkdevice and whose ARQ ACK has not been received before a certain timepoint after the target network device satisfies the second condition.

In some implementations of the present application, the communicationdevice 600 may be a source network device.

Specifically, when a network device connected with a terminal device isswitched from the source network device to a target network device, theconnection between the terminal device and the source network device andthe connection between the terminal device and the target network deviceare both maintained. The network device includes the communication unit610; wherein when the target network device satisfies a secondcondition, the communication unit 610 sends and/or receives a packetdata convergence protocol (PDCP) protocol data unit (PDU) by using a newsecret key and/or robust header compression (RoHC), wherein the newsecret key and/or RoHC is different from an old secret key and/or RoHC,and the old secret key and/or RoHC is a secret key and/or RoHC which isused before updating during communication of the terminal device/thetarget network device.

Optionally, the communication unit 610 is specifically configured to:send and/or receive the PDCP PDU by using the new secret key and/or RoHCafter the target network device satisfies the second condition and aftera certain time interval.

Optionally, the communication unit 610 is further configured to: sendand/or receive the PDCP PDU by using the old secret key and/or RoHCwithin a certain time after the target network device satisfies thesecond condition.

Optionally, the second condition includes at least one of the following:the target network device has sent a handover command, or the sourcenetwork device has received indication information sent by the terminaldevice or the target network device for indicating the source networkdevice to send and/or receive the PDCP PDU by using the new secret keyand/or RoHC.

Optionally, the communication unit 610 is further configured to: receivethe indication information.

Optionally, the communication unit 610 is specifically configured to:receive the indication information sent by the terminal device when atleast one of the following is satisfied: the terminal device hasreceived the handover command, the terminal device has initiated arandom access procedure, the terminal device has sent a handovercompletion message, the terminal device has sent a message 1, theterminal device has received a message 2, the terminal device has sent amessage 3, or the terminal device has sent a message 4.

Optionally, the communication unit 610 is specifically configured to:receive indication information sent by the target network device when atleast one of the following conditions is satisfied: the target networkdevice has received handover completion information, the target networkdevice has received the message 1, the target network device has sentthe message 2, the target network device has received the message 3, andthe target network device has sent the message 4.

Optionally, the communication unit 610 is further configured to: receivea first data packet retransmitted by the terminal device.

Optionally, the communication unit 610 is specifically configured to:receive the first data packet retransmitted by the terminal device byusing the old secret key and/or ROHC, or by using the new secret keyand/or RoHC.

Optionally, the communication unit 610 is more specifically configuredto: receive the first data packet retransmitted by the terminal device,and decrypt and/or decompress the PDCP PDU corresponding to the firstdata packet according to the old secret key and/or RoHC, or according tothe new secret key and/or ROHC.

Optionally, the communication unit 610 is further configured to: discarda third data packet, wherein the third data packet is a data packet thatwas not successfully sent before the source network device satisfies thesecond condition and/or before a certain time point after the sourcenetwork device satisfies the second condition.

Optionally, the communication unit 610 is further configured to:retransmit a third data packet to the terminal device, wherein the thirddata packet is a data packet that was not successfully sent before thesource network device satisfies the second condition and/or before acertain time point after the source network device satisfies the secondcondition.

Optionally, the communication unit 610 is specifically configured to:retransmit the third data packet to the terminal device by using the oldsecret key and/or ROHC, or by using the new secret key and/or RoHC.

Optionally, the third data packet includes a PDCP PDU which has beensent by the source network device and whose automatic repeat requestacknowledgement (ARQ ACK) has not been received before the sourcenetwork device satisfies the second condition, and/or the third datapacket includes a PDCP PDU which has been sent by the source networkdevice and whose ARQ ACK has not been received before a certain timepoint after the source network device satisfies the second condition.

FIG. 9 is a schematic block diagram of a terminal device 700 accordingto an implementation of the present application. Optionally, when anetwork device connected with the terminal device is switched from asource network device to a target network device, the connection betweenthe terminal device and the source network device and the connectionbetween the terminal device and the target network device are bothmaintained.

As shown in FIG. 9, the terminal device 700 may include: a trigger unit710; wherein when the terminal device satisfies a first condition, thetrigger unit is configured to trigger the terminal device to send apacket data convergence protocol (PDCP) status report.

Optionally, the first condition includes at least one of the following:the terminal device has received a handover command, the terminal devicehas initiated a random access procedure, or the terminal device has senta handover completion message.

Optionally, the random access procedure initiated by the terminal deviceincludes at least one of the following cases: the terminal device hassent a message 1, the terminal device has received a message 2, theterminal device has sent a message 3, or the terminal device hasreceived a message 4.

Optionally, the trigger unit 710 is specifically configured to: triggerthe terminal device to send the PDCP status report after the terminaldevice satisfies the first condition for a certain time.

It should be understood that the apparatus implementations maycorrespond to the method implementations with each other, anddescription of the method implementations may be referred to for similardescription of the apparatus implementations. Specifically, thecommunication device 500 shown in FIG. 7 may correspond to acorresponding entity performing the method 200 of the implementation ofthe present application, the communication device 600 shown in FIG. 8may correspond to a corresponding entity performing the method 300 ofthe implementation of the present application, and the communicationdevice 700 shown in FIG. 9 may correspond to a corresponding entityperforming the method 400 of the implementation of the presentapplication, which is not repeated here again for the sake of brevity.

The communication device according to an implementation of the presentapplication is described from a perspective of functional module abovewith reference to FIGS. 7 to 9. It should be understood that thefunctional module may be realized in form of hardware, or instructionsin form of software, or a combination of hardware and software modules.

Specifically, each act of the method implementations in theimplementations of the present application can be implemented byhardware integrated logic circuits and/or instructions in the form ofsoftware in a processor, and the acts of methods disclosed withreference to the implementations of the present application may bedirectly executed and implemented by a hardware decoding processor, ormay be implemented by a combination of hardware and software modules inthe decoding processor.

Optionally, the software modules may be located in a storage mediumcommonly used in the art, such as a random access memory, a flashmemory, a read-only memory, a programmable read-only memory, anelectrically erasable programmable memory, or a register, etc. Thestorage medium is located in the memory, and the processor readsinformation in the memory and completes the acts of the above methodimplementations in combination with its hardware.

For example, in an implementation of the present application, therelease unit shown in FIG. 7 may be implemented by a processor, and thecommunication unit 610 shown in FIG. 8 and the trigger unit 710 shown inFIG. 9 may be implemented by transceivers.

FIG. 10 is a schematic diagram of a structure of a communication device800 according to an implementation of the present application. Thecommunication device 800 shown in FIG. 10 includes a processor 810,wherein the processor 810 may call and run a computer program from amemory to implement the method in an implementation of the presentapplication.

Optionally, as shown in FIG. 10, the communication device 800 mayfurther include a memory 820. The memory 820 may be configured to storeindication information, or may be configured to store codes,instructions, etc., executed by the processor 810. The processor 810 maycall and run a computer program from the memory 820 to implement themethod in the implementation of the present application.

Herein, the memory 820 may be a separate device independent of theprocessor 810 or may be integrated in the processor 810.

Optionally, as shown in FIG. 10, the communication device 800 mayfurther include a transceiver 830, and the processor 810 may control thetransceiver 830 to communicate with another device. Specifically,information or data may be sent to another device or information or datasent by another device is received.

Herein, the transceiver 830 may include a transmitter and a receiver.The transceiver 830 may also further include antennas, and a quantity ofantennas may be one or more.

Optionally, the communication device 800 may be a source network deviceor a target network device according to an implementation of the presentapplication, and the communication device 800 may implementcorresponding processes implemented by the source network device or thetarget network device in various methods of the implementations of thepresent application. That is to say, the communication device 800according to an implementation of the present application may correspondto the corresponding entity performing the methods 200 to 400 accordingto the implementations of the present application, which is not repeatedhere again for the sake of brevity.

Optionally, the communication device 800 may be a terminal deviceaccording to an implementation of the present application, and thecommunication device 800 may implement the corresponding processesimplemented by the terminal device in various methods of theimplementations of the present application. That is to say, thecommunication device 800 according to an implementation of the presentapplication may correspond to the corresponding entity performing themethods 200 to 400 according to the implementations of the presentapplication, which is not repeated here again for the sake of brevity.

It should be understood that the various components in the communicationdevice 800 are connected through a bus system. In addition to a databus, the bus system further includes a power bus, a control bus, astatus signal bus, etc.

In addition, an implementation of the present application furtherprovides a chip, which may be an integrated circuit chip with a signalprocessing capability, and can implement or execute the methods, actsand logic block diagrams disclosed in the implementations of the presentapplication.

Optionally, the chip may be applied to various communication devices, sothat the communication devices with the chip installed therein canperform the disclosed methods, acts and logic block diagrams in theimplementations of the present application.

FIG. 11 is a schematic diagram of a structure of a chip according to animplementation of the present application.

A chip 900 shown in FIG. 11 includes a processor 910. The processor 910may call and run a computer program from a memory to implement themethod in the implementation of the present application.

Optionally, as shown in FIG. 11, the chip 900 may further include amemory 920. Herein, the processor 910 may call and run a computerprogram from the memory 920 to implement the method in theimplementation of the present application. The memory 920 may beconfigured to store indication information, or may be configured tostore codes, instructions, etc., executed by the processor 910.

Herein, the memory 920 may be a separate device independent of theprocessor 910 or may be integrated in the processor 910.

Optionally, the chip 900 may further include an input interface 930. Theprocessor 910 may control the input interface 930 to communicate withanother device or chip. Specifically, information or data sent byanother device or chip may be acquired.

Optionally, the chip 900 may further include an output interface 940.The processor 910 may control the output interface 940 to communicatewith another device or chip. Specifically, information or data may beoutput to another device or chip.

Optionally, the chip may be applied in a network device of theimplementation of the present application, and the chip may implementthe corresponding processes implemented by the network device in variousmethods of the implementations of the present application, which is notrepeated here again for brevity.

Optionally, the chip may be applied to a terminal device in animplementation of the present application, and the chip may implementthe corresponding processes implemented by the terminal device invarious methods of the implementations of the present application, whichis not repeated here again for the sake of brevity.

It should be understood that the chip mentioned in the implementation ofthe present application may also be referred to as a system-level chip,a system chip, a chip system or a system-on-chip, etc. It should also beunderstood that the various components in the chip 900 are connectedthrough a bus system. Herein, in addition to a data bus, the bus systemfurther includes a power bus, a control bus, a status signal bus, etc.

The processor may include, but is not limited to: a general purposeprocessor, a digital signal processor (DSP), an application specificintegrated circuit (ASIC), a field programmable gate array (FPGA), oranother programmable logic device, a discrete gate or a transistor logicdevice, or a discrete hardware component, etc.

The processor may be configured to implement or perform methods, actsand logical block diagrams disclosed in the implementations of thepresent application. The acts of the method disclosed with reference tothe implementation of the present application may be directly embodiedas executed and completed by a hardware decoding processor, or may beexecuted and completed by a combination of hardware and software modulesin a decoding processor. The software modules may be located in astorage medium commonly used in the art, such as a random access memory,a flash memory, a read-only memory, a programmable read-only memory oran erasable programmable memory, a register, etc. The storage medium islocated in a memory, and the processor reads information in the memoryand completes the acts of the above method in combination with itshardware.

The memory includes but is not limited to: a volatile memory and/or anon-volatile memory. Herein, the non-volatile memory may be a Read-OnlyMemory (ROM), a Programmable ROM (PROM), an Erasable PROM (EPROM), anElectrically EPROM (EEPROM), or a flash memory. The volatile memory maybe a Random Access Memory (RAM), which is used as an external cache.Through an exemplary but not limitative description, many forms of RAMsmay be used, for example, a Static RAM (SRAM), a Dynamic RAM (DRAM), aSynchronous DRAM (SDRAM), a Double Data Rate SDRAM (DDRSDRAM), anEnhanced SDRAM (ESDRAM), a Synchlink DRAM (SLDRAM), and a Direct RambusRAM (DRRAM).

It should be noted that the memory in the systems and the methodsdescribed in this specification are aimed at including but being notlimited to these and any memory of another suitable type.

An implementation of the present application further provides a computerreadable storage medium, configured to store a computer program. Thecomputer readable storage medium stores one or more programs includinginstructions which, when executed by a portable electronic deviceincluding multiple application programs, enables the portable electronicdevice to perform the methods of the implementations shown as methods200 to 400.

Optionally, the computer readable storage medium may be applied in anetwork device of an implementation of the present application, and thecomputer program enables ae computer to perform the correspondingprocesses implemented by the network device in various methods ofimplementations of the present application, which is not repeated hereagain for the sake of brevity.

Optionally, the computer readable storage medium may be applied in amobile terminal/terminal device of an implementation of the presentapplication, and the computer program enables the computer to performthe corresponding processes implemented by the mobile terminal/terminaldevice in various methods of implementations of the present application,which is not repeated here again for the sake of brevity.

An implementation of the present application further provides a computerprogram product, including a computer program.

Optionally, the computer readable storage medium may be applied in anetwork device of an implementation of the present application, and thecomputer program enables the computer to perform the correspondingprocesses implemented by the network device in various methods ofimplementations of the present application, which is not repeated hereagain for the sake of brevity.

Optionally, the computer readable storage medium may be applied in amobile terminal/terminal device of an implementation of the presentapplication, and the computer program enables the computer to performthe corresponding processes implemented by the mobile terminal/terminaldevice in various methods of implementations of the present application,which is not repeated here again for the sake of brevity.

An implementation of the present application further provides a computerprogram. When the computer program is executed by a computer, thecomputer can perform the method of the implementations shown as themethods 200 to 400.

Optionally, the computer program may be applied in a network device ofan implementation of the present application. When the computer programis run on the computer, the computer is enabled to perform thecorresponding processes implemented by the network device in variousmethods of implementations of the present application, which is notrepeated here again for the sake of brevity.

An implementation of the application further provides a communicationsystem, which includes the terminal device, the source network deviceand the target network device as described above.

It should be noted that the term “system” in this specification may alsobe referred to as “network management architecture” or “network system”,etc.

It should also be understood that the terms used in implementations ofthe present application and the appended claims are for the purpose ofdescribing specific implementations only but are not intended to limitimplementations of the present application.

For example, the singular forms “a”, “said”, “the above” and “the” usedin the implementations of the present application and the appendedclaims are also intended to include the plural forms unless the contextclearly indicates other meanings.

Those skilled in the art may recognize that the exemplary elements andalgorithm acts described in combination with the implementationsdisclosed herein can be implemented in electronic hardware, or acombination of computer software and electronic hardware. Whether thesefunctions are executed in hardware or software depends on a particularapplication and a design constraint condition of a technical solution.Those skilled in the art may use different methods to implement thedescribed functions in respect to each particular application, but suchrealization should not be considered to be beyond the scope ofimplementations of the present application.

The function units may be stored in a computer readable storage mediumif realized in a form of software functional units and sold or used as aseparate product. Based on this understanding, the technical solution ofimplementations of the present application, in essence, or the partcontributing to the existing art, or a part of the technical solution,may be embodied in a form of a software product. The computer softwareproduct is stored in a storage medium, including a number ofinstructions for enabling a computer device (which may be a personalcomputer, a server, or a network device, or the like.) to perform all orpart of the acts of the methods described in various implementations ofthe present application. And the aforementioned storage medium includesvarious kinds of media that may store program codes, such as a USB flashdisk, a removable hard disk, a Read-Only Memory (ROM), a Random AccessMemory (RAM), a magnetic disk or an optical disk, etc.

Those skilled in the art may clearly learn that for convenience andconciseness of description, the specific working processes of thesystems, apparatuses and units described above may refer to thecorresponding processes in the aforementioned method implementations andis not repeated here again.

In several implementations provided by the present application, itshould be understood that the disclosed systems, devices and methods maybe implemented in another mode. For example, the division of the units,modules or components in the above-mentioned device implementations isonly a logical function division, and there may be another division modein an actual realization. For example, multiple units, modules orcomponents may be combined or integrated into another system, or someunits or components may be ignored or not executed.

For another example, the units/modules/components described above asseparate/display components may or may not be physically separated,i.e., they may be located in one place or may be distributed overmultiple network units. Part or all of the units/modules/componentstherein may be selected according to an actual requirement to achieve apurpose of a solution the implementations of the present application.

Finally, it should be noted that the mutual coupling or direct couplingor communication connection shown or discussed in the above may beindirect coupling or communication connection through some interface,apparatus or unit, and may be in electrical, mechanical or other forms.

What are described above are merely specific implementations of thepresent application, but the protection scope of implementations of thepresent application is not limited thereto. Any variation orsubstitution that may be easily conceived by a person skilled in the artwithin the technical scope disclosed by the present application shall beincluded within the protection scope of the present application.Therefore, the protection scope of the implementations of the presentapplication shall be determined by the protection scope of the claims.

What is claimed is:
 1. A method for wireless communication, applied to aPacket Data Convergence Protocol (PDCP) entity in a target networkdevice, wherein when a terminal device is switched from a source networkdevice to the target network device, a connection between the terminaldevice and the source network device and a connection between theterminal device and the target network device are both maintained; themethod comprises: after sending a message 4 of a random access procedureto the terminal device, receiving, a PDCP protocol data unit (PDU) byusing a new secret key and/or robust header compression (RoHC); whereinthe new secret key is different from an old secret key, the new RoHC isdifferent from an old RoHC; the old secret key or the old RoHC is usedin communicating between the terminal device and the source networkdevice.
 2. The method of claim 1, further comprising: determining that acondition that the terminal device has initiated the random accessprocedure.
 3. The method of claim 1, wherein a first data packetcomprising a PDCP PDU has been sent by the terminal device and whoseautomatic repeat request acknowledgement (ARQ ACK) has not been receivedbefore the terminal device has received the message of 4 of the randomaccess procedure.
 4. The method of claim 3, wherein the method furthercomprises: receiving, by the target network device, the first datapacket retransmitted by the terminal device, wherein, receiving, by thetarget network device, the first data packet comprises: decryptingand/or decompressing, by the target network device, the first datapacket according to the new secret key and/or ROHC.
 5. The method ofclaim 1, wherein receiving a packet data convergence protocol (PDCP)protocol data unit (PDU) comprises: receiving the PDCP PDU from at leasttwo Radio Link Control protocol (RLC) entities.
 6. A network device,wherein the network device is used a target network device, comprising aPacket Data Convergence Protocol (PDCP) entity, wherein when a terminaldevice is switched from a source network device to the target networkdevice, a connection between the terminal device and the source networkdevice and a connection between the terminal device and the targetnetwork device are both maintained; the target network device furthercomprises a memory and a processor, wherein the processor is configuredto execute instructions stored in the memory to perform followingoperations comprising: after sending a message 4 of a random accessprocedure to the terminal device, receiving, a PDCP protocol data unit(PDU) by using a new secret key and/or robust header compression (RoHC);wherein the new secret key is different from an old secret key, the newRoHC is different from an old RoHC; the old secret key or the old RoHCis used in communicating between the terminal device and the sourcenetwork device.
 7. The network device of claim 6, wherein receiving thePDCP PDU comprises: determining that a condition that the terminaldevice has initiated a random access procedure.
 8. The network device ofclaim 7, wherein a first data packet comprising a PDCP PDU has been sentby the terminal device and whose automatic repeat requestacknowledgement (ARQ ACK) has not been received before the terminaldevice has received the message 4 of the random access procedure.
 9. Thenetwork device of claim 8, wherein the processor is specially configuredto execute instructions stored in the memory to perform followingoperation: receiving the first data packet retransmitted by the terminaldevice, and decrypting and/or decompressing the first data packetaccording to the new secret key and/or ROHC.
 10. The network device ofclaim 6, wherein the processor is further configured to executeinstructions stored in the memory to perform following operation:receiving the PDCP PDU from at least two Radio Link Control protocol(RLC) entities.